For the orthographic projection as a map projection, see Orthographic projection in cartography. For mathematical discussion in terms of linear algebra, see Projection (linear algebra).
Bullfrogs are the largest real frog found in North America, weighing up to 0.5 kg and measuring 460 mm in length. Their average length is 100-175 mm. Their color varies from brownish to shades of green, often with spots or blotches of a darker color around their backs. Their back feet are fully webbed.
The juveniles are green to brown with a peppering of tiny black spots, and have orange or bronze eyes. A fold of skin extends from the eye around the eardrum. Adult bullfrogs have thickset bodies, large, exposed eardrums, and are green, tan, or dark brown above (with dark spots). Male bullfrogs have a yellow throat. The eardrums on males are larger than the eyes, while the female's eardrums are the same size as the eyes. The eyes of both sexes are gold.